The present invention relates to clip-on sunglasses and more particularly to an improved enclosed spring bridge mechanism for clip-on sunglasses that enables the sunglasses to be easily mounted on eyeglasses.
Clip-on sunglasses consist of a metal or plastic frame that carries a pair of light attenuating plastic or glass lenses. A mechanism is provided to removably mount the clip-on sunglasses on the frame of eyeglasses.
In order to be commercially acceptable, the clip-on sunglasses must be light in weight, reasonably rugged and relatively inexpensive. They must also be easy to mount on and remove from eyeglasses. Further, the clip-on sunglasses must mount without damaging the eyeglasses, particularly the lenses.
One common type of mounting mechanism is a clamp that is attached to the bridge of the sunglasses. The clamp typically includes pairs of opposing prongs which are spring-loaded toward each other so as to retain the lenses of the eyeglasses between the prongs. Examples of this clamp-type mechanism are disclosed in U.S. Pat. No. 3,575,497 issued Apr. 20, 1971 to Leblanc, U.S. Pat. No. 5,164,749 issued Nov. 17, 1992 to Shelton and U.S. Pat. No. Des 350,359 issued Sep. 6, 1994 to Friedman.
However, clamp-type mechanisms have their disadvantages. The prongs must clamp tightly to the lenses, potentially scratching the lenses. The mechanism may obstruct the view partially. Moreover, the clamp-type mechanisms have several inter-engaging parts which must be fabricated precisely and assembled, making the mechanism relatively expensive and sometimes unreliable.
In order to overcome the drawbacks of the clamp-type mechanisms, a mechanism was developed for mounting clip-on sunglasses that does not contact or clamp the lenses of the eyeglasses and therefore cannot scratch them. This type of mechanism utilizes one or more sets of exposed spring-loaded prongs. The prongs are movably or flexibly mounted such that they can be moved against a spring force, for insertion between spaced portions of the eyeglasses frame. The spring force causes the prongs to frictionally engage the eyeglasses frame. Because the prongs only engage the frame, the lenses of the eyeglasses cannot be scratched. An example of such a mechanism is disclosed in U.S. Pat. No. 5,953,096 entitled xe2x80x9cUniversal Center Bridge Mounting Mechanism for Clip-On Sunglasses xe2x80x9d issued to me on Sep. 14, 1999.
Another type of clip-on sunglasses, such as is disclosed in Lockwood U.S. Pat. No. 2,926,563, consists of mirror image frame sections, each of which consists of a lens and a bridge element. The bridge elements are connected together by a bridge mechanism that includes an exposed metal coil spring. The mechanism permits the frame sections to move away from each other, against the force of the spring. Each frame section, at its outer extremity, is provided with a set (typically two or three) of eyeglasses frame engaging prongs protruding from the plane of the lens sections. When the frame sections are moved away from each other, against the force of the spring, the eyeglasses frame can be inserted between the prongs. Releasing the frame sections permits the spring to move frame sections back toward each other, such that the eyeglasses frame is securely retained between the prongs.
One problem inherent in the Lockwood type spring bridge mechanism is that the coil spring is exposed. Aside from being unsightly, this is undesirable because bits of solid debris and other particulate foreign matter can lodge between the coils and jam the mechanism or distort the spring. Liquid, such as rain or sweat, can enter the mechanism resulting in rusting or deterioration of the parts. Further, the skin, hair and eyebrows of the user are not protected from the exposed spring.
I therefore developed an improved spring bridge mechanism that overcomes the exposed spring problem by enclosing the coil spring within a slender tubular enclosure. The enclosure isolates the spring from the skin and hair of the wearer and prevents debris and liquids from reaching the spring.
The enclosure serves the additional purpose of keeping the frame sections in the proper plane as they are moved. This is achieved by a slot in the enclosure which cooperates with a protrusion to maintain the frame sections in the same plane. The interior wall of the enclosure also provides an end surface for the spring to abut.
Aside from isolating the spring from the environment, the enclosure enhances the appearance of the clip-on sunglasses by hiding the unsightly spring. Preferably, the enclosure is made of the same material and finish as the bridge elements and frame, resulting in a mechanism which is much less conspicuous than an exposed spring.
I received U.S. Pat. Nos. 6,234,628 and 6,302,538, issued May 22, 2001 and Oct. 16, 2001, respectively, for my enclosed spring bridge mechanism. The clip-on sunglasses disclosed in those patents, as well as the clip-on sunglasses disclosed in Lockwood, require sets of protruding prongs mounted on opposite sides of the lens sections of the sunglasses to receive the eyeglasses frame. However, the prongs on the lens sections are unsightly and because the prongs must protrude out of the plane of the sunglasses, they may catch on other objects and make it difficult to store the sunglasses.
The need for protruding prongs on clip-on sunglasses can be avoided by providing spaced engaging parts on the eyeglasses frame and mounting the sunglasses by moving the lens retaining frame sections of the sunglasses toward each other and inserting the sunglasses between the engaging parts on the frame of the eyeglasses. That structure is disclosed in my co-pending application Ser. No. 10/273533, filed Oct. 21, 2002 and entitled xe2x80x9cEyeglasses and Clip-On Sunglasses Therefor.xe2x80x9d
I am aware of U.S. Pat. No. 5,801,804, issued Sep. 1, 1998 to Robert Pennise, entitled xe2x80x9cLinearly Adjustable Sunglasses xe2x80x9d that discloses clip-on sunglasses that do not require protruding prongs. In Pennise, the lens sections of the sunglasses are moved toward each other in order to mount the sunglasses, as in my co-pending application Ser. No. 10/273,533. However, Pennise""s clip-on sunglasses are designed to mount between the temple pieces of the eyeglasses frame, and hence behind the lenses of the eyeglasses, making the sunglasses uncomfortable to wear and hence impractical. Moreover, Pennise""s sunglasses require a second bridge part, spaced from the spring bridge, to maintain the lenses in the same plane.
Although the clip-on sun glasses structure disclosed in my co-pending application Ser. No. 10/273533 noted above works well, it requires specially fabricated eyeglasses, which could be considered to be a drawback. I have therefore invented improved clip-on sunglasses that function in a manner similar to the structure disclosed in U.S. Pat. Nos. 6,234,628 and 6,302,538, in that specially fabricated eyeglasses are not required and the frame sections are moved apart for mounting. However, the improved clip-on sunglasses have the spring bridge mechanism located between and directly connected to the frame sections, similar to that disclosed in my co-pending application Ser. No. 10/273533, such that the bridge elements are eliminated, resulting in a simpler, more aesthetically pleasing structure.
It is, therefore, a prime object of the present invention to provide improved clip-on sunglasses with an enclosed spring bridge mechanism attached directly to and between the lens sections, that does not require specially fabricated eyeglasses.
It is another object of the present invention to provide improved clip-on sunglasses with an enclosed spring bridge mechanism that is simple and aesthetically pleasing.
In accordance with the present invention, clip-on sunglasses is provided including first and second sections. Each of the sections includes a lens, a rim at least partially surrounding the lens and an eyeglasses engaging prong mounted to the rim. Means for connecting the first and second sections for movement between a proximate position and a remote position are provided. The connecting means includes a first tubular member connected to the rim of the first section, a second tubular member connected to the rim of the second section and spring means for urging the sections toward the proximate position.
The first tubular member is received within the second tubular member. The spring means is at least partially received within the first tubular member.
Means are provided for preventing relative rotation between the tubular elements. The rotation preventing means includes a protrusion on one of the tubular members and a protrusion receiving slot in the other member. The slot is elongated in the direction of movement of the sections.
The spring means includes a spring with first and second ends. The first spring end is fixed to the rim of the first section. The second spring end is fixed to the rim of the second section.
Preferably, a second eyeglass engaging prong is located on each of the sections. The second prong is spaced from the first prong. The connecting means forms the bridge of the sunglasses. It is situated between the first and the second sections.